It depends on which character set you want to use.
There’s no tab entity defined in ISO-8859-1 HTML – but there are a couple of whitespace characters other than such as , ,and .
In ASCII, is a tab.
Here is a complete listing of HTML entities and a useful discussion of whitespace on Wikipedia.
It’s much cleaner to use CSS. Try padding-left:5em or margin-left:5em as appropriate instead.